Just as it appeared Congress was closer to overturning long-standing U.S. policy by easing Cuba travel restrictions for Americans, the provision, now part of an omnibus spending bill, appears stalled in the Senate.

If passed, the bill, introduced in the House on February 4, would grant U.S. citizens and legal residents the right to visit Cuba as well as allow Cuban Americans to send money to relatives and visit them more often.

House Democrats opted to attach the bill's language to a broader, $410 billion omnibus spending bill that is needed to pass so the 12 Cabinet departments and other agencies can keep running. The House passed the bill on February 25 by a margin of 245-178.

Now, however, Democratic Sen. Robert Menendez of New Jersey and Republican Sen. Mel Martinez of Florida, both of Cuban descent, are leading the fight to block the bill in the Senate.

Both senators urged colleagues to vote against the spending bill because the change in U.S.-Cuban foreign policy is attached to it.

On Sunday night, Sen. Harry Reid of Nevada canceled a final procedural vote that would have cleared the way for passage because the bill was one vote shy of attaining 60 votes, the number needed to avoid an opposing filibuster. Debate continued throughout the day on Monday, with neither side able to compromise.

President Obama is expected to sign the bill, should it reach his desk.